Non-Aqueous Electrolytic Solutions and Electrochemical Cells Comprising the Same

Inactive Publication Date: 2016-10-13
SHENZHEN CAPCHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a non-aqueous electrolytic solution for lithium batteries that has high capacity retention, long cycle life, and reduced swelling. The solution includes a combination of cyclic carbonate, linear asymmetric carbonate, sultone, and phosphazene compound. These additives help to form a good solid-electrolyte interface on the negative electrode surface, improve the stability of the electrolyte, and interact better with the electrodes, resulting in batteries with low swelling problems and high performance.

Problems solved by technology

However, in many cases the SEI protection from conventional electrolytes with simple formulations such as LiPF6 in mixtures of EC and linear carbonates is insufficient in lithium ion batteries where the negative electrode materials are carbonaceous materials including graphite carbons and non-graphite carbons, for example inexpensive natural graphite (a kind of graphite carbon) and hard carbon (a kind of amorphous non-graphite carbon), which exhibits a higher initial discharge capacity but quickly loses capacity in subsequent cycles.
Swelling of lithium ion batteries is a commonly encountered problem, especially with above-mentioned nickel-rich cathode materials.
The swelling, as demonstrated by an increase in thickness as in prismatic cells, may cause rupture of the case or increase of required space for battery packs.
Besides, swelling is usually accomplished by resistance increase, open-cell voltage decrease and / or capacity loss of the cell.
The problem is especially significant when the cells are stored in a charged state at elevated temperatures.
Each approach has its problems.
For example, capacity retention of the cells may deteriorate.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

examples

[0035](1) Preparation of a Cathode. A positive electrode slurry was prepared by dispersing LiCoO2 (as positive electrode active material, 90 wt percent), poly(vinylidenfluoride) (PVdF, as bonder, 5 wt percent), and acetylene black (as electro-conductive agent, 5 wt percent) into 1-methyl-2-pyrrolidone (NMP). The slurry was coated on aluminum foil, dried, and compressed to give a positive electrode.

[0036](2) Preparation of an Anode. Artificial graphite (as negative electrode active material, 95 wt percent) and PVdF (as binder, 5 wt percent) were mixed into NMP to give a negative active material slurry which was coated on copper foil, dried, and pressed to give a negative electrode

[0037](3) Preparation of Electrolytic Solutions. The Baseline Electrolyte is formed by blending 61.0 g LiPF6 into 161.1 g EC and 277.9 g EMC to give 500 g baseline electrolyte. To the baseline electrolyte, 0 to 2 wt percent of different additive combination were added to create the electrolyte samples 1 to 6...

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Abstract

A lithium secondary battery having reduced swelling tendency includes an electrolytic solution. The electrolytic solution includes a lithium salt, a cyclic carbonate, a linear asymmetric carbonate, a third carbonate, a sultone and a phosphazene compound.

Description

FIELD OF THE INVENTION[0001]This application is a CON of Ser. No. 13 / 012,832 filed Jan. 25, 2011. The entire disclosure of the aforesaid application is incorporated herein in its entirety by reference[0002]The present invention relates to a non-aqueous electrolytic solution and an electrochemical energy storage device comprising the same. More particularly, this invention pertains to non-aqueous electrolytic solutions that comprise (a) one or more solvents; (b) one or more ionic salts; and (c) one or more additives. Non-aqueous electrolytic solutions capable of protecting either negative electrode materials, such as lithium metal and carbonaceous materials, or positive electrode materials, such as metal composite oxide containing lithium, or both, in energy storage electrochemical cells (e.g., lithium metal batteries, lithium ion batteries and supercapacitors) include a cyclic carbonate, a linear carbonate, a sultone, and a phosphazene compound. Such electrolyte solutions enhance th...

Claims

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Application Information

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IPC IPC(8): H01M10/0567H01M10/052H01M10/0568H01M10/0569H01M4/133H01M4/583H01M4/66H01M4/62H01M4/131H01M10/0525H01M4/525
CPCH01M10/0567H01M10/0525H01M10/052H01M10/0568H01M10/0569H01M4/133H01M4/583H01M4/661H01M4/622H01M4/625H01M4/131H01M4/525H01M4/382H01M4/386H01M4/463H01M4/466H01M4/485H01M4/505Y10T29/49108Y10T29/4911Y02E60/10Y02P70/50Y02T10/70
InventorLI, WENTAOPAYNE, MARTIN W.
OwnerSHENZHEN CAPCHEM TECH